from www.latimes.com – Investigators have concluded that Rebecca Zahau, the girlfriend of pharmaceutical executive Jonah Shacknai, committed suicide at his Coronado mansion, according to Zahau’s sister, who was briefed by San Diego County Sheriff’s Department detectives.

Mary Zahau-Loehner, in emails and interviews, told reporters Thursday night that the family does not believe Zahau took her own life.

But San Diego County Sheriff Bill Gore, backed by detectives and the medical examiner, plans a news conference Friday morning to explain how forensic evidence and interviews with people who talked to Zahau in the days before her death led to the overwhelming conclusion that she committed suicide and was not the victim of foul play.

Zahau may have been despondent over a sense of responsibility for the injury suffered by Shacknai’s 6-year-old son Max during a time when Zahau was supposed to be watching him.

Retired San Diego homicide Det. Rick Carlson, who was not involved in the case but has investigated hundreds of traumatic deaths and written a book about suicides, said one sign that sheriff’s detectives have concluded it was suicide was that they have not named a “person of interest” who might have killed Zahau.

Zahau’s nude body was found in the courtyard of the historic Spreckels mansion on the morning of July 13. Her hands and feet had been tied, a noose was around her neck, a rope was tied to a second-story balcony.

She had apparently jumped off a small table in the courtyard. Her lifeless body was found by Shacknai’s brother, Adam, a guest at the mansion.

Almost immediately, a media-fanned “mystery” suggested that the 32-year-old Zahau may have been murdered.

But investigators said that it is not unknown for suicide victims to tie their hands and feet to avoid having “second thoughts.” The Sheriff’s Department delayed making its determination until forensic tests were completed and interviews done to assess Zahau’s mental state; Shacknai, his brother, and his ex-wife were interviewed.

Two days before Zahau’s death, Max Shacknai suffered what proved to be a fatal fall when he tumbled down the staircase inside the Ocean Boulevard mansion.

The home was built in 1908 by John D. Spreckels, a major business and philanthropic figure in San Diego in the first third of the past century.

Jonah Shacknai , 54, was not at home when Zahau’s body was found by his brother. Shacknai and his ex-wife, Dina, were keeping a vigil at their son’s bedside.

Max Shacknai died July 17 at Rady Children’s Hospital, a week after the fall. He had never regained consciousness. His organs were donated for transplant.

“His loving, kind and vibrant spirit will forever be in our hearts and those whom he touched every day,” Shacknai said in an email announcing his son’s death.

Shacknai is chairman and chief executive of the firm he founded, Medicis Pharamaceutical Corp., based in Scottsdale, Ariz., a leader in skin care and beauty aid products. He is active in charitable organizations, including funding the Whispering Hope Ranch Foundation, which pairs special needs children with abused, abandoned or injured animals.

Zahau, whose married name was Rebecca Nalepa, was an ophthalmic technician in the Phoenix area before quitting her job to spend more time with Shacknai and his children. After a divorce, she took back her maiden name.

Shacknai, twice divorced, lives most of the year in the affluent community of Paradise Valley, Ariz., to be near his business. The Coronado house was considered a summer home.